7 Needs context
In Brad Petek's study of approximately 1,600 collegiate athletes with COVID-19, only two athletes (0.06%) experienced symptoms lasting longer than 12 weeks.
"1,600 in Brad Petek's study. What percentage do you think? Make a guess. ... Yeah, 0.06%: two people, two out of 1,600." (said at 0:07:05)
In a prospective observational cohort study from the Outcomes Registry for Cardiac Conditions in Athletes (ORCCA) led by Dr. Bradley Petek (PMID 34725052), 3,597 collegiate athletes with SARS-CoV-2 infection were evaluated. Data on persistent symptoms were available for 3,529 athletes. Exactly 2 athletes (0.06%) experienced persistent symptoms lasting longer than 12 weeks. The speaker correctly reported the exact number of affected athletes (2) and the exact percentage (0.06%), but misstated the total sample size as 1,600 rather than 3,529 (2 out of 3,529 is 0.06%, whereas 2 out of 1,600 would be 0.125%).
One year of intensive endurance training in healthy 70-year-old sedentary adults improved cardiorespiratory fitness but failed to alter heart structure or compliance.
"we took our healthy seniors and we trained them for a year. We used the same training program that we used in a group of young people... and they got fitter for sure, but we didn't change their heart structure at all, not even a little bit. So once you got to be age 70, it was virtually impossible to change the heart structure." (said at 0:19:55)
The speaker refers to a prospective interventional study conducted by their research group (Fujimoto et al., 2010) in which 9 previously sedentary older adults (mean age 70.6 years) underwent 1 year of progressive and vigorous endurance training. The training significantly improved cardiorespiratory fitness (VO2max increased by 19%) but failed to reverse age-associated cardiac stiffening or improve left ventricular (LV) compliance. However, saying the intervention 'didn't change their heart structure at all, not even a little bit' is a slight overstatement: the study did document modest physiological LV remodeling, with LV mass increasing by 10% (P = 0.037) without altering the mass-to-volume ratio.
- partial: Cardiovascular effects of 1 year of progressive and vigorous exercise training in previous… (Circulation 2010) · cited 230x in the literature
"One year of exercise training had little effect on cardiac compliance. However, it reduced arterial elastance and improved Vo(2)max by 19% (22.8±3.4 versus 27.2±4.3 mL/kg/mL; P<0.001). LV mass increased (10%, 64.5±7.9 versus 71.2±12.3 g/m(2); P=0.037) with no change in the mass-volume ratio. Although 1 year of vigorous exercise training did not appear to favorably reverse cardiac stiffening in sedentary seniors, it nonetheless induced physiological LV remodeling and imparted favorable effects on arterial function and aerobic exercise capacity." (abstract, results and conclusions, passage verified)
pubmedfull study (doi) - context: Plasticity of the heart in response to changes in physical activity. (The Journal of physiology 2025) · cited 9x in the literature
"Specifically, older adults who initiate endurance training later in life are unable to improve ventricular compliance and diastolic function, suggesting reduced cardiac plasticity with advanced age; however, lifelong exercise training prevents age-associated cardiac remodelling and maintains cardiac compliance of older adults at a level similar to those of younger healthy individuals." (abstract, results, passage verified)
pubmedfull study (doi)
Research by Jonathan Myers and the Cooper Clinic shows that individuals who improve their fitness over time gain a survival advantage equivalent to those who maintained high fitness, whereas those who lose fitness lose that advantage.
"I think the other thing to be careful about is there is some data from the Cooper Clinic mostly, but also from others—Jonathan Myers at the VA in California has shown that if you measure fitness at one particular point in time, people who gain fitness gain advantage equivalent to people who have sustained fitness, and people who lose fitness lose that advantage." (said at 0:59:07)
Large prospective cohort studies from the Cooper Center Longitudinal Study (Blair et al., 1995) and Veterans Affairs cohorts (Kokkinos, Myers, et al., 2023) confirm that cardiorespiratory fitness is dynamic: increasing fitness over time significantly reduces all-cause mortality, whereas losing fitness substantially increases mortality risk regardless of baseline fitness. However, the claim that individuals who improve fitness achieve a survival advantage strictly equivalent to those with sustained high fitness needs qualification: in the landmark Cooper Clinic study, men who improved from unfit to fit reduced their mortality risk by 44% compared to persistently unfit men (67.7 vs. 122.0 deaths per 10,000 man-years), but their mortality rate remained higher than those who maintained fitness at both assessments (39.6 per 10,000 man-years).
- supports: Changes in Cardiorespiratory Fitness and Survival in Patients With or Without Cardiovascul… (Journal of the American College of Cardiology 2023) · cited 129x in the literature
"In general, changes in CRF ≥1.0 MET were associated with inverse and proportionate changes in mortality risk regardless of baseline CRF status. For example, a decline in CRF of >2.0 METS was associated with a 74% increase in risk (HR: 1.74; 95% CI: 1.59-1.91) for low-fit individuals with CVD, and 69% increase (HR: 1.69; 95% CI: 1.45-1.96) for those without CVD." (abstract, results, passage verified)
pubmedfull study (doi) - context: Changes in physical fitness and all-cause mortality. A prospective study of healthy and un… (JAMA 1995) · cited 1969x in the literature
"The highest age-adjusted all-cause death rate was observed in men who were unfit at both examinations (122.0/10,000 man-years); the lowest death rate was in men who were physically fit at both examinations (39.6/10,000 man-years). Men who improved from unfit to fit between the first and subsequent examinations had an age-adjusted death rate of 67.7/10,000 man-years. This is a reduction in mortality risk of 44% (95% confidence interval, 25% to 59%) relative to men who remained unfit at both examinations." (abstract, results, passage verified)
pubmed
In Laura DeFina's 2019 JAMA study of 25,000 Cooper Clinic patients, 75% of participants had coronary artery calcium scores below 100, and among them, high physical activity was associated with a 50% reduction in cardiovascular events with no difference in calcium levels.
"And so that's where our Cooper Clinic study came in, Laura DeFina's paper in JAMA from 2019. We looked at 25,000 people with multiple different ranges of physical activity, from the middle group, which is sort of that guideline-directed three to five hours a week, a low group who did less than three hours a week, and then high-volume exercisers who did about eight hours a week. Okay? And it turned out that about 75% of all three groups, about 75% of them had relatively little coronary calcium... there was no difference in coronary calcium among the three different activity groups and a 50% reduction in events." (said at 2:07:30)
The 2019 study led by Laura DeFina in JAMA Cardiology evaluated 21,758 generally healthy men from the Cooper Center Longitudinal Study. Approximately 75.6% (16,444 of 21,758) of participants had coronary artery calcium (CAC) scores below 100 Agatston units. Among men with CAC < 100, high physical activity (≥3,000 MET-min/week) was associated with a 48% reduction in all-cause mortality compared to low physical activity (<1,500 MET-min/week; HR 0.52, 95% CI 0.29–0.91). However, contrary to the statement that there was 'no difference in coronary calcium,' high physical activity was actually associated with a modest but statistically significant increase in the prevalence of CAC ≥ 100 (relative risk 1.11, 95% CI 1.03–1.20), though this elevated CAC did not confer an increased risk of mortality.
- context: Association of All-Cause and Cardiovascular Mortality With High Levels of Physical Activit… (JAMA cardiology 2019) · cited 206x in the literature
"A total of 21 758 generally healthy men without prevalent cardiovascular disease (CVD) were included... The CAC scores were categorized into at least 100 (n = 5314) and less than 100 (n = 16 444) Agatston units (AU)... Men with at least 3000 MET-min/wk were more likely to have prevalent CAC of at least 100 AU (relative risk, 1.11; 95% CI, 1.03-1.20) compared with those accumulating less physical activity... Men with CAC of less than 100 AU and physical activity of at least 3000 MET-min/wk were about half as likely to die compared with men with less than 1500 MET-min/wk (hazard ratio [HR], 0.52; 95% CI, 0.29-0.91)." (abstract, results)
pubmedfull study (doi)
The Pro@Heart study demonstrated increased coronary plaque associated with high-intensity endurance activity in young and older elite athletes.
"the Pro@Heart study that I mentioned to you before kind of threw a big wrench into this because they looked at elite young and older athletes, and they did show more plaque related to high-intensity endurance activity." (said at 2:11:00)
The speaker conflated two related studies from the same research group: the Pro@Heart study and the Master@Heart study. The Master@Heart study (PMID: 36881712) evaluated 191 lifelong master endurance athletes, 191 late-onset athletes (median age 55), and 176 healthy controls, finding that lifelong endurance exercise was associated with increased coronary plaque burden (odds ratio 1.86 for >=1 coronary plaque), including non-calcified proximal plaques. In contrast, the Pro@Heart study (PMID: 35368514) is a prospective cohort study investigating cardiac remodeling, genetics, and arrhythmias in young elite endurance athletes aged 14 to 23 years, rather than coronary atherosclerosis.
Studies by Guido Claessen and André La Gerche show that during exercise, increased heart rate and closed-valve time cause atrial dilation due to blood damming, which increases the risk of atrial fibrillation.
"There's a very elegant study by again Guido Claessen and André La Gerche, which talks about the damming effect of the valves... And now the other thing it does is it increases the heart rate, and when you increase the heart rate, now you have more cycles. So instead of having the valve open, now it's, and you spend more time with those valves closed, and so it creates a dam in between the atria and the ventricles, and the atria just dilate. And as you dilate the atria, you increase the risk of atrial fibrillation." (said at 2:14:45)
Research co-authored by Guido Claessen and André La Gerche (such as PMIDs 32757003 and 41775865) documents that endurance exercise leads to atrial enlargement and hemodynamic stretch, which increases the risk of atrial fibrillation (AF) in endurance athletes. However, the specific biomechanical explanation that high heart rate causes a "damming effect" due to increased closed-valve duration during exercise is a theoretical/mechanistic interpretation rather than a validated empirical finding from their published studies. The literature primarily attributes exercise-induced atrial dilation to sustained high cardiac output, volume overload, and hemodynamic stretch rather than valve closure time dynamic damming.
A Cooper Clinic analysis of individuals performing more than 10,000 MET-minutes of exercise per week found zero cardiovascular deaths and no increase in overall mortality.
"And in fact, we presented at the American Heart Association a few years ago: we looked at the Cooper Clinic database, we looked at more than 10,000 MET-minutes a week. This was stimulated by Amby Burfoot, by the way, who asked us this question: "What about, you know, you say only eight hours a week? That's nothing for many of my runners." Or he said, "Okay, these average guys average 30 hours a week." And there was no increase in mortality, there was no increase in events. It wasn't a lot of people, it was twice the number in the Copenhagen heart study, by the way. You know how many cardiovascular deaths? Zero." (said at 2:22:45)
The speaker references an American Heart Association conference presentation analyzing extreme exercise volumes (>10,000 MET-minutes/week) in the Cooper Center Longitudinal Study database. In published, peer-reviewed analyses from this cohort, high-volume physical activity (categorized as ≥3,000 MET-minutes/week) was similarly found to have no increased risk of myocardial infarction or composite coronary events, and was associated with a significant 29% reduction in all-cause mortality compared to low activity. The specific conference sub-analysis evaluating the extreme >10,000 MET-minutes/week tier was presented as preliminary conference findings rather than published as a standalone peer-reviewed endpoint.
Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.